Substituting carbon for nitrogen in g-CN enhances π-electrons activity and photocatalytic performance, despite the challenges posed by the higher electronegativity of nitrogen. We successfully achieved the substitution of C atoms for N atoms via the copolymerization of melamine and cytosine utilizing the Schiff base reaction, altering the g-CN band structure from 2.74 to 2.49 eV and enhancing photoinduced electron reduction due to the introduction of −N-C = C- unit into the g-CN network. The C-incorporated g-CN extended the light-response range to 673 nm and improved the electron cloud density around the self-doping sites, significantly reducing the ΔG as indicated the DFT results, implying the efficient separation and migration of photoinduced carriers in g-CN. As anticipated, the photocatalytic hydrogen evolution (PHE) rate of the optimized C self-doped g-CN was five and seven times higher than that of the pristine g-CN under the full spectrum and the visible light (λ ≥ 400 nm), respectively. Moreover, g-CN- also display superior activity (6.73, 4.48, 3.42, and 0.76 %) under the different wavelengths (λ = 420, 450, 480 nm, and 540 nm respectively). This report reveals a subtle atom-tailoring scheme to control carbon self-doping sites within the g-CN framework, modulating its inherent electronic properties and photoactivity.

中文翻译：

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DFT 和表面精密碳自掺杂多孔 g-C3N4 机械分析的见解，用于增强可见光驱动的析氢


尽管氮的较高电负性带来了挑战，但用碳代替 g-CN 中的氮增强了 π 电子活性和光催化性能。我们利用席夫碱反应，通过三聚氰胺和胞嘧啶的共聚，成功实现了 C 原子对 N 原子的取代，将 g-CN 能带结构从 2.74 eV 改变为 2.49 eV，并由于引入 -N-C = C 增强了光诱导电子还原- 单位进入 g-CN 网络。掺入 C 的 g-CN 将光响应范围扩展至 673 nm，并提高了自掺杂位点周围的电子云密度，显着降低了 DFT 结果所示的 ΔG，这意味着 g-CN 中光生载流子的有效分离和迁移-CN。正如预期的那样，在全光谱和可见光（λ≥400nm）下，优化的C自掺杂g-CN的光催化析氢（PHE）速率分别比原始g-CN高5倍和7倍，分别。此外，g-CN- 在不同波长（分别为 420、450、480 nm 和 540 nm）下也表现出优异的活性（6.73、4.48、3.42 和 0.76%）。该报告揭示了一种微妙的原子定制方案，可以控制 g-CN 框架内的碳自掺杂位点，调节其固有的电子特性和光活性。